This invention relates to a flexible pouch such as is used in the packaging of processed cheese, and to a method of opening it for inserting product. Such pouches are generally opened by gripping the top margin of each side of the pouch with vacuum means and pulling the sides away from each other. The vacuum means grips the flat pouch at four locations which are intended to form the four corners of the rectangularly-shaped open pouch. After the pouch is opened on its top margin, a ram descends into the pouch from the top, completely opening and shaping the pouch to its full designed volume and shape. In some instances, the top margin of the pouch is not opened properly by the vacuum means, such that the margin is improperly formed into some shape other than a rectangle having four straight edges. The improperly formed margin may then be impacted by the descending ram, and pushed ahead of the ram, such that the pouch is at least partially crumpled by the ram. Such improperly formed pouches cannot be used, and thus must be discarded as waste. Further, the flow of packaged product from the packaging operation is interrupted, incurring all the costs associated with such failures.
Apparatus has been developed for assisting in consistently forming sharp-cornered rectangles in the top margin of the pouch. For example U.S. Pat. No. 4,150,519 teaches suction cup apparatus specifically designed to assist in location and forming of the corners. Copending application Ser. No. 081,528 filed Oct. 3, 1979, shows a suction box modified to control the gripping of the pouch.
It is an object of this invention to provide an improved pouch which can be reliably formed into a rectangular receptacle having on its open margin sharp corners at predetermined locations.
It is a further object to provide a method for opening the pouch, the method ensuring that the top margin of the pouch will conform to the required shape when it is opened.